An outboard engine unit is disclosed in, e.g., Japanese Patent Application Laid-Open Publication No. 10-175594 (JP 10-175594 A).
FIG. 6 hereof shows the outboard engine unit disclosed in JP 10-175594 A. Referring to FIG. 6, a cover for the outboard engine unit 200 disclosed in JP 10-175594 A has an upper cover 201 for covering an engine, a middle cover 202 disposed below the upper cover 201, a lower cover 203 disposed below the middle cover 202, and a gear case 205 disposed below the lower cover 203.
The middle cover 202 covers a lower portion of the engine. The lower cover 203 covers a drive shaft connected to a crankshaft of the engine. The gear case 205 covers a gear mechanism connected to the drive shaft. A propeller 204 is connected to the gear mechanism and is rotated via the drive shaft by the driving of the engine.
FIGS. 7A and 7B show in simplified form the structure of the middle cover 202 and the lower cover 203 for the outboard engine unit shown in FIG. 6.
In FIG. 7A, the middle cover 202 is configured so as to be divided in two on the left and right sides to form a left middle cover 206 and a right middle cover 207. The lower cover 203 is similarly configured so as to be divided in two on the left and right sides to form a left lower cover 208 and a right lower cover 209.
A very small gap 211 is formed between the cover 206 and the cover 207 when the left middle cover 206 and the right middle cover 207, as well as the left lower cover 208 and the right lower cover 209, are joined together in the cover for the outboard engine unit disclosed in JP 10-175594, as shown in FIG. 7B. In order to remove the gap 211, the end face 212 of the right middle cover 207 is trimmed to flatten the end face 212, but the edging requires time and effort. When time and effort are required for the edging, the result is that the outboard engine unit is assembled less efficiently.